Internal-combustion turbine



Dec. 24, 1946. GRlFFlTH 2,413,225

INTERNAL-COMBUSTION TURBINE Filed 001?. 7, 1943 3 Sheets-Sheet l 770iMimic-m flTTofiA/EY NYE NTO.

1946' A. A. GRIFFITH INTERNAL-COMBUSTION TURBINE Filed Oct. 7, 1943 3Sheets-Sheet 2 k/wzwToR 5% 1946' A. A. GRIFFITH 2,413,225

INTERNAL-CQMBUSTION TURBINE Filed Oct. 7, 1943 3 Sheets-Sheet 3 fiORA/EY Patented Dec. 24, 1946 INTERNAL-COMBUSTION TURBINE Alan ArnoldGrifiith, Derby, England, assignor to Rolls-Royce Limited, Derby,England, a British company Application October 7, 1943, Serial No.505,392

In Great Britain May 14, 1941 This application corresponds to theapplication of Alan Arnold Griffith, Serial No. 6209/41, which was filedin Great Britain on May 14, 1941.

This invention relates to internal-combustion engines working on a cyclewherein heating takes place ata constant pressure and may, for example,be applied to turbine power-units of the kind described in thespecification of my United States application Serial No. 505,389.

Since the air for combustion is compressed to the maximum workingpressure in a turbine of the kind above set forth, its temperature israised and for some purposes it is desirable to have available a supplyof cool high-pressure air. Such air may be used, for example, in aconstruction of turbine as described in the specification of my UnitedStates application Serial No. 505,391, in which high-pressure air isused for balancin the end-thrust on the rotor elements.

This invention accordingly comprises an internal-combustion turbinewherein high-pressure air from the compressor extracted for auxiliaryuses is cooled by the fuel which is passing to the burner.

According to another feature of this invention, it comprises in aturbine, the combination with a plurality of separately rotatablerotor-elements, of a central shaft carrying them which shaft is hollowand open at one end to the delivery end of the compressor, and isprovided along its length with Openings to the spaces between thebearings and the rotor elements, and an air-cooler through whichgoiehiuel, on its way to the burner, is circulated to' cool the airentering the shaft.

According to another feature of this invention, the air-cooler aforesaidcomprises a plurality of nested hollow cooling elements each ofcylindrical form and so dimensioned radially to permit airflow axiallybetween them. Alternatively, the aircooler aforesaid may be ofsubstantially disc-like construction, and in either case is mountedadjacent the end of the rotor-shaft at the high-pressure end of thecompressor to receive air therefrom.

In the accompanying drawings:

Figure 1 is a central sectional view showing the application of thisinvention to an internal-combustion turbine of the kind described in thespecification of my application Serial No. 505,391,

Figure 21s a part sectional view on the line 2-2 of Figure 1,

Figure 3 is a part sectional view on the line 33 of Figure 1, and

Figure 4 is a central sectional view of a modified construction of aircooler.

6 Claims. (Cl. .60-41) Referring first to Figures 1 to 3,aninternalcombustion turbine power-unit comprises a central stationaryshaft ill on which there are mounted a number of separate rotor-elementsll each carrying air-compressor blades I2 and turbine blades I3. Each ofthese rotor elements H is mounted by its own bearings M on the shaft Inso as to be rotatable independently of the other elements, and thevarious elements are separated by thrust-bearings I5. Thecompressor-blades I2 deliver the high-pressure air past stationaryguide-vanes Hi to an annular chamber H from which it passes to anysuitable form of oil-fuelburner indicated generally by the reference It,being guided thereto by the stationary vanes 20. The products ofcombustion from the burner pass into the space 2| and thence throughstationary guide-vanes 22 to the turbine-blades l3, to drive the unit.

The shaft l0 carrying the rotor-elements is hollow as indicated at 23and a fuel supply pipe 24 is centrally situated in this shaft, extendingfrom its rear end to the forward open end 25 of the shaft. This shaft I0is furthermore provided with radial openings 26 giving accessto thespaces between the various rotor-elements.

The air-cooler forming the subject-matter of this invention is situatedin a stationary housing 21, 28 of cylindrical form surrounding the openend 25 of the shaft 19 and in the construction illustrated in Figure 1,it comprises a number of hollow cylindrical shells 29 mounted coaxiallyand nested one within the other. These shells are so dimensionedradially as to provide axial air spaces between them. The air entersthese spaces by openings 30 from the annular chamber l1 and circulatesaxially backwards and forwards as indicated by the arrows in the lowerpart of Figure 1 between the various shells 29 and then passes by theopenings 3! to the space at the end of the shaft It! so that it can thenenter the open end 25 thereof and pass out by the openings 26 aforesaid.

The oil supply which is effected through the pipe 24 above described isled therefrom by openings 32 to the interior of the innermost shell 29and circulates therefrom through all the other shells in series, finallypassing from the outermost one by the passage 33 to the burner. It willbe seen that the air enters the cooler at its'outer periphery and sweepsover all the cooling elements, whilst the oil follows a similar butreverse path giving a counter-flow cooling whereby the air iseffectively cooled and the oil is heated.

In order to provide adequate cooling surfaces,

the air-spaces between the elements 29 may be provided with corrugatedmetal strips 34 arranged endwise to the direction of flow of air toabsorb heat from the air and transmit it by direct conduction to theshells 29.

In the' alternative construction illustrated in Figure 4, the air-cooleris constituted by a series of hollow disc-like elements 40; theseelements are arranged co-axially with the shaft I and receive the oilfrom the fuel-supply pipe 24 by the openings 3| which communicate withthe inner periphery of the first element 40. The oil thus passesradially outwards in the first element 40 and is transferred by theconnections 4| at its outer periphery to the second element so that ittravels radially inwards therein, and so on until it is finallydelivered from the last element by the passage 42 to a burner indicatedgenerally by the reference 43.

The air which is to be cooled enters the housing 44 of the cooler by theopenings 45 from the highpressure end of the compressor and circulatesradially inwards and outwards across all the cool ing elements 40,finally passing out by the opening 46 to the space surrounding the openend of the shaft l0, so that the cooled air can flow therethrough andout by the openings 26 to the rotor elements.

It will be seen that the heat-exchanger or aircooler in either of theforms above-described, is subjected to the high-pressure air on itsoutside, but this is balanced by the pressure of the fuelsupply on theinside, and since the fuel is supplied to the burner at a pressuresubstantially equal to that of the air, the pressures are balanced andit is possible to use a very light construction of cooling device andensure a high efficiency of heat-transfer. These pressure conditionsexist under all working conditions of the power-unit so that no specialprecautions in this respect are required. It is found that the coolingeffect available with the fuel-oil for a turbodriven compressor issufficient to cool the small quantity of air which is required forbalancing the end-thrust on the rotor elements; a definite air-flow toassist in cooling the rotor-elements may be provided for, but in anycase there is a certain amount of leakage-flow which is effective forthe same purpose.

I claim:

1. In an internal-combustion turbine power plant, the combination ofaturbine, an air compressor driven thereby, and supplying air thereto,means for supplying fuel to said turbine, means for extracting a portionof the air compressed by said compressor, means for causing saidextracted air to be cooled by the fuel supplied to said turbine andmeans for conveying the cooled air to its place of utilization.

2. In an internal-combustion turbine power plant, the combination of aplurality of separately rotatable rotor elements, a central shaftsupporting said elements, said shaft being hollow and open at one end,an air compressor whereof the delivery communicates with said hollowshaft to supply compressed air thereto, openings in said shaft providingcommunication from the interior thereof to the spaces between said rotorelements, means for supplying liquid fuel to said turbine. and an aircooler cooled by said liquid fuel and disposed between the outlet fromthe compressor and said hollow shaft.

3. In an internal-combustion engine power plant, the combination of aturbine, a compressor driven thereby and supplying air thereto, meansfor delivering air compressed by said compressor to the turbine elementsand their bearings, an air cooler comprising a plurality of nestedhollow cooling elements each of cylindrical form and so dimensionedradially as to permit air flow axially between them, means for supplyingliquid fuel to said turbine through said air cooler, and means directingthe cooling air for the turbine elements through said cooler.

4. In an internal-combustion turbine power plant, the combination of aturbine including rotor elements, an air compressor driven by saidturbine, means for supplying fuel to said turbine, a plurality ofco-axial cylindrical cooling elements, means for causing the liquid fuelto pass through some of said elements, means for delivering some of theair from said compressor between said cooling elements, and means forsupplying said cool air to said rotor elements.

5. In an internal-combustion turbine power plant, the combination of aturbine including rotor elements, an air compressor driven thereby, anair cooler comprising a plurality of hollow disc-like elements, meansfor supplying liquid fuel through said elements, means for passing aportion of the air compressed by said compressor between said elementsto cool it, and means for delivering the cool air to said rotor elementsto cool them.

6. In an internal-combustion turbine power plant, the combination of ahollow shaft open at one end and provided with radial openings atintervals along its length, a plurality of rotor elements rotatablymounted on said shaft, with turbine blades on each of said elements,compressor blades on each of said elements for compressing air, a burnerchamber, means for delivering compressed air to said chamber, means fordelivering the products of combustion to said turbine blades, an aircooler, means for supplying liquid fuel therethrough to said burnerchamber, means providing communication from the delivery chamber of saidair compressor blades to said air cooler, and means for delivering aircooled in said air cooler to the interior of said hollow shaft andthence to the spaces between said rotor elements to cool them.

ALAN ARNOLD GRIEFTTI-I.

